This is one big wingspan! This is the ARF version I have converted to electric power. I bid on an Ebay auction for the kit version and received this instead. I was thinking the kit would be easier to add the motor and spoilers but who can complain when you get something for half price? I actually was/am really psyched about the fiberglass fuselage and the construction seems really good. That gi-normous wing is actually in three pieces so it is easier to transport than the Gentle Lady! Well, in order to make an omelet. so the saying goes. I started by sawing off the nose right at the width of the spinner so it would look right. That still left me with solid steel to cut through and 3/8" left on the nose for a firewall. This kit is for "tow" launching so there is a solid steel plug in the nose for ballast. I just need to cut the front off so I could use the rest as a motor mount to mount the motor from the inside. After I had fretted long enough about just were to cut, I put some masking tape around the outside to keep the fiberglass from splintering and secured it in a miter box and went to town with the hack saw. It took a while and a couple blades, but I finally got al the way through. I used a bench grinder to flatten the nose a bit. I think, the only airplane I'll ever use a bench grinder on. Then all that was left was to drill out the mounting holes for the motor and screw it in. It actually came out pretty well! So, how do you cool something like this in flight? A glider is supposed to be very smooth so a scoop is out of the question. Hmmm. I decided to hinge the canopy in the back and add a micro servo to raise and lower it with the throttle so, that, at full throttle, the canopy is open almost a half inch and it is closed when the motor is off. There is a little collet to secure the canopy and allow the canopy to be released to change the battery. Check out the photos below to see how it works. At this point I was ready for a flight so I took it out to a club with lots of room and it flew great! The AXI2820 has plenty of power. It does want to climb over its back so a bit of down elevator helps keep an aggressive climb. There was one mishap when I pulled out of a dive, the wing made an audible *CRACK*. The wing seemed strong enough, but I brought it in and got a lesson in just how "ground affect" operates. I bet that thing could go 300 yards at three feet off the deck. Amazing, but either you have to fly it into the ground or you have to shoot five approaches to get it down.
The need for spoilers was clear. I decided on the Graupner Thin Tall Spoilers for their minimal footprint and ease of installation. They were a little more difficult to install than I anticipated. I ended up cutting back all the white covering on the top center section of the wing and then there was the issue of how to articulate them. I decided to fashion a bit of shock cord to the mechanism to act as a return so all I would have to do is pull them. I only wanted one servo concealed in the fuselage. It is actually mounted like an aileron servo. Seems to work. The spoilers are meant to be mounted a tad below grade so you can add balsa over them and attach your covering to that. My only complaint was that for the price of these buggers, I expected them to be flawless. Instead one had a pin that would work its self loose and jam the mechanism. It took a couple hours of futzin' to get it to work smoothly. The last thing I wanted was for one spoiler to retract while the other jammed.
So what about that crack? There was a split in the very center of the wing along the bottom. I think the sheeting just snapped, but I didn't want to chance it so I mixed up some 20 minute epoxy and using a large syringe and needle, I "injected" epoxy into the center section of the wing. That did it!
It was then time for another test flight. Back out to the same location and up it went. It flew great! I had added a bit of yellow to the bottom of the wing for visibility and that helped a lot. T this point, it was time to test those spoilers. With lots of altitude and wings level, I deployed them. Up they went and down the glider went! Quickly, I might add. The glider picked up a fair amount of speed but with a bit of elevator, I could level the descent. They did just what they were supposed to do and so in a bit it was time to try them for real and land. No surprises. It just flew like it weighed three times as much. The spoilers were a success!
It is a majestic bird in the sky with a wing plan form like no other. I did learn that the rudder becomes very sluggish at slow speeds so if the turn isn't happening, then just hit the power and around it goes. Lovely glider. It was a bit of work converting everything, but well worth it. For a build log on the WattFlyer Blog, click HERE. For Spoiler info, click HERE.
Specs are as follows:
Below are some photos (sorry no flight photos yet. Too much futzin' Soon though...):